thalidomide and liver cirrhosis

In: Liver Cirrhosis: Causes, Diagnosis and Treatment ISBN 978-1-61209-248-5

Editor: Miranda L. Michelli © 2011 Nova Science Publishers, Inc.

Chapter 1

Thalidomide and its Analogs: A

Potential Immunomodulatory

Alternative for Treating Liver

Diseases and Cirrhosis

Eduardo Fernández-Martínez*

Laboratory of Medicinal Chemistry and Pharmacology

Cuerpo Académico de Biología de la Reproducción,

Área Académica de Medicina del Instituto de Ciencias de la Salud (I.C.Sa.)

Universidad Autónoma del Estado de Hidalgo (UAEH)

Abstract

Thalidomide is currently used for treating erythema nodosum leprosum, multiple

myeloma, angiogenesis, rheumatoid arthritis, graft-versus-host disease, among others.

Thalidomide effects are related to its capacity to inhibit the proinflammatory cytokine

tumor necrosis factor-α (TNF-α) and, in consequence, causes immunomodulation on

other cytokines. During the establishment of some diseases the balance between

proinflammatory and antiinflammatory cytokines is disrupted, promoting a pathological

state; thus, elevated levels of proinflammatory cytokines mediate several deleterious

processes such as inflammation, necrosis, apoptosis and fibrosis. These events are present

in acute and chronic degenerative liver diseases such as hepatitis, cholangitis, cirrhosis

and hepatocellular carcinoma (HCC). Then, the immunomodulation on cytokines by

drugs seems to be a pharmacological target to ameliorate liver damage and cirrhosis. In

fact, there are not sufficient drugs for relief or cure of cirrhosis currently; some of these

* Address: Calle Dr. Eliseo Ramírez Ulloa no. 400,

Colonia Doctores, Pachuca, Hidalgo, México

C.P. 42090

Telephone: (52) +7717172000 ext. 4510 and 4512

E-mail: [email protected] and [email protected]

The exclusive license for this PDF is limited to personal website use only. No part of this digital document may be reproduced, stored in a retrieval system or transmitted commercially in any form or by any means. The publisher has taken reasonable care in the preparation of this digital document, but makes no expressed or implied warranty of any kind and assumes no responsibility for any errors or omissions. No liability is assumed for incidental or consequential damages in connection with or arising out of information contained herein. This digital document is sold with the clear understanding that the publisher is not engaged in rendering legal, medical or any other professional services.

Eduardo Fernández-Martínez 2

few are expensive, unstable and palliative or may cause side effects. Novel thalidomide

analogs have been synthesized with improved stability and potency as TNF-α inhibitory

and immunomodulatory agents, besides low or none teratogenicity. Experimental

assessment of thalidomide and its analogs in animal models of liver injury have afforded

very hopeful outcomes. Thalidomide and two analogs have evidenced anticholestatic,

antinecrotic and antifibrotic activities in bile duct ligation-induced biliary cirrhosis.

Another analog protected D-galactosamine/endotoxin-treated mice from liver damage.

Thalidomide ameliorated the alcoholic hepatic injury and prevented necrosis, cholestasis

and fibrosis induced by CCl4 in rats. Moreover, this drug salvaged from lethal hepatic

necroinflammation and accelerated the recovery from established thioacetamide-

provoked cirrhosis in rats. The antiinflammatory, antinecrotic and antifibrotic effects

elicited by thalidomide and its analogs are mainly mediated by the inhibition on TNF-

through two different routes, as well as the down-regulation of nuclear factor-B (NF-

B) signaling pathway and by diminishing adhesion molecules to prevent the progression

of liver fibrosis and cirrhosis. Furthermore, thalidomide showed beneficial effects on

HCC by decreasing angiogenesis and metastasis in murine models; therefore, diverse

clinical phase I/II studies were carried out to evaluate its antitumoral or disease control

outcomes. However, thalidomide as a single drug therapy yields very modest benefits,

although in most cases this is well tolerated and offers disease stabilization. Different

doses and the combination with other chemotherapeutic agents appear to enhance

therapeutic effects; the assessment of the new thalidomide analogs in next clinical trials

of HCC healing is strongly suggested. Thalidomide and its analogs may be a feasible

option for the treatment of liver diseases and cirrhosis.

Introduction

History of Thalidomide

Thalidomide (Tha, -N-phthalimidoglutarimide, Figure 1) was first synthesized in

Germany in 1954 by the pharmaceutical company Chimie-Grünenthal GmbH. The former

intended use for Tha was as a mild hypnotic-sedative agent similar to barbiturates but without

their addictive or toxic effects (Keller et al., 1956; Somers, 1960). Grünenthal introduced Tha

since 1956 in Germany wherein that was approved in 1957 as a safe sedative drug for sales

over the counter. Soon thereafter, this drug was marketed in other countries including United

Kingdom, the rest of Europe, New Zealand, Australia, Japan and Canada under the brand

names such as “Contergan, Distaval, Talimol, Kevadon and Softenon”; however, Tha was

never approved in United States because the Food and Drug Administration requested more

information from Grünenthal concerning peripheral neuritis reports (Fullerton et al., 1961;

Marriott et al., 1999; Teo, 2005). Meanwhile, Tha had been considered as a virtually non-

toxic drug, due to its very low acute toxicity in rodent models (Somers, 1960; Williams,

1968); in addition, Tha became a very common sleep-inducing agent with very good

antiemetic properties and, consequently, it began to be used by pregnant women for treating

the nausea due to morning-sickness in the first trimester of gestation (Marriott et al., 1999;

Teo, 2005). The reports of birth defects and deformed babies emerged at the end of 1956 to

1961, thus the strong suspicion regarding teratogenicity by Tha in man grew up; finally, in

1961 Lenz (1961; Lenz, 1992) published the first paper suggesting that Tha was responsible

for limb deformities in newborn infants, this suggestion was rapidly confirmed by others as

Thalidomide and its Analogs 3

well as experimentally in rabbits (McBride, 1961; Somers, 1962; Williams, 1968). Due to

those terrible cases of amelia and phocomelia, ranging from 10000-12000 children around the

world, Tha was withdrawn from the market in November 26, 1961 and during 1962.

Nevertheless, by 1965 this agent had evidenced antiinflammatory properties, because Sheskin

(1965) administered Tha as a sedative to leprosy patients suffering from erythema nodosum

leprosum (ENL, a severe dermatological complication of Hansen´s disease formerly known as

leprosy) and found amazing effects, given that clinical signs and symptoms of ENL were

attenuated within 48 h. Such discovery established the basis to the future increased interest on

Tha mechanism of action and the synthesis of novel safer analogs with non-teratogenic

effects, as well as the further applications in the treatment of several inflammatory,

degenerative and chronic diseases.

Figure 1 Thalidomide chemical structure.

Thalidomide Chemical Properties

The chemical name of Tha is 2-(2,6-dioxo-3-piperidinyl)-1H-isoindole-1,3(2H)-dione

and it is composed by two imide moieties, the phthalimide ring and the glutarimide ring; its

empiric formula is C13H10N2O4, with a molecular weight of 258.2 g/mol. Tha is a white,

tasteless crystalline powder with a melting point of 269-271°C. This drug is sparingly soluble

in water (6 mg/100mL), methanol, ethanol, acetone, and glacial acetic acid but readily soluble

in acetone, dioxane, dimethyl formamide, pyridine, chloroform, and dimethyl sulfoxide. It is

insoluble in ether and benzene (Somers, 1960). Its low solubility in water would suggest that

its concentration in body fluids at any time would be small (Williams, 1968), so the efforts to

get Tha dissolved have led to prepare solutions in alkaline pH that promotes the spontaneous

hydrolysis of Tha; in consequence, such solutions contain Tha in addition to its hydrolysis

products. The main route of hydrolysis of Tha at pH 6, 7.4 and 8 is cleavage of the

phthalimido ring to α-(o-carboxybenzamido)glutarimide; this compound is reasonably stable

at these pH values, however, as the pH is increased the bonds of glutarimide ring become

susceptible to hydrolysis and, at pH 7.4 and 8 especially, considerable amounts of 2- and 4-

phthalimidoglutaramic acids are formed (Schumacher et al., 1965a). It suggests that Tha

biological effects may also be shared by its hydrolysis products or its metabolites, thus, this

compound may act as a prodrug for one or more of those Tha derivatives (Fabro et al., 1965;

Muller et al., 1996). In addition, Tha possesses a single chiral center in the glutarimide ring,

an asymmetric carbon that originates the R and S enantiomers; thus, Tha is administered as a

racemic mixture of (-)-(S)- and (+)-(R)-enantiomeric forms. It has been demonstrated for Tha


that there is a relationship between quirality and its biological effects (Blaschke et al., 1979);

this point will be commented farther on.

Thalidomide and its Analogs: Characteristics and Mechanisms of Action

Nowadays, Tha has showed several mechanisms of action as an antiinflammatory and

immunomodulatory drug because of its broad range of inhibitory and stimulatory effects on

the immune system (Zwingenberger and Wnendt, 1995; Mujagić et al., 2002). However, so

far the most plausible mechanism is the inhibition on the production of the important,

pleiotropic, pronecrotic and proinflammatory cytokine tumor necrosis factor-α (TNF-α)

(Sampaio et al., 1991), through enhancing the TNF-α mRNA degradation (Moreira et al.,

1993). On this way, other authors have proposed that Tha has also immunomodulatory

activity by two more routes: a) reducing the number of IgM plaque-forming cells and b)

enhancing the secretion of the cytokine interleukin-2 (IL-2) in peripheral blood mononuclear

cells (PBMC) (Shannon et al., 1997). Regarding other immunomodulatory effects, it has been

observed that Tha has a costimulatory role in the upregulation of T helper 2 (Th2)-type

immunity, because Tha increases the production of Th2-type (humoral) cytokines, for

example interleukin-4 (IL-4) and interleukin-5 (IL-5); as well as inhibits the production of the

Th1-type (cellular) cytokine interferon-γ (IFN-γ) in PBMC (McHugh et al., 1995; Marriott et

al., 1999), while in T cells Tha induces a high production of IFN-γ and IL-2 (Corral et al.,

1999).

There are other possible immunomodulatory and/or regulatory mechanisms of Tha on

diverse endogen mediators of the immune and inflammatory response. It deserves special

consideration the first report concerning the inhibition on the activation of the nuclear factor-

κB (NF-κB) in HIV-infected primary macrophages (Moreira et al., 1997). NF-κB is a

transcription nuclear factor that has received much attention since its discovery in 1986,

because of its activation by many different stimuli and its diverse and prominent roles in

maintaining the homeostasis, control of disease development, regulation of cell survival and

activation of innate and adaptive immune responses, for instance, its activation provokes the

production of proinflammatory cytokines including the most potent TNF-α (Sun and Karin,

2008). On this way, there are reports that support that Tha strongly suppresses at different

levels the NF-κB activation induced by TNF-α and reactive oxygen species (ROS) such as

H2O2, besides this inhibition is apparently not cell type specific, although these effects are not

seen during the NF-κB activation by other inducers (Majumdar et al., 2002; Kim et al., 2004).

This likely mechanism of action has prompted the design and synthesis of NF-κB inhibitors

derived from Tha (Carcache de-Blanco et al., 2007).

Cyclooxigenase-2 (COX-2) is the inducible enzyme that catalyzes the synthesis of

prostaglandins (PG) which are very well known potent endogen proinflammatory agents and

that regulate the cytokines expression. COX-2 is induced by bacterial lipopolysaccharides

(LPS) and it has been considered as a pharmacological target for the prevention and treatment

of angiogenesis and cancer; indeed, Tha has evidenced promising effects as inhibitor of LPS-

induced COX-2 (Fujita et al., 2001). Furthermore, novel Tha analogs have been recently

synthesized and/or evaluated as inhibitors of COX-2 (Suizu et al., 2003; Fujimoto et al.,

2006).


Other via of regulation by Tha is achieved through diminishing the nitric oxide (NO)

production and its multiple biological actions by two possible ways, a) decreasing the TNF-α

synthesis, since this cytokine as well as interleukin-1β (IL-1β) and IFN-γ are important

mediators of NO production, because they regulate the expression of the inducible nitric

oxide synthase (iNOS) (López-Talavera et al., 1996) and b) it has been also demonstrated that

Tha possesses weak but significant inhibitory activity on iNOS, what encouraged the

synthesis of Tha-related inhibitors of NOS (Shimazawa et al., 2004); moreover, some authors

have designed their counterpart, some NO-donating Tha analogs as anticancer agents (Wang

et al., 2009).

There is another feasible immunomodulatory mechanism of action of Tha, it has been

showed that this drug binds to a pair of proteins identified as isoforms of the α1-acid

glycoprotein (α1-AGP), suggesting a potential role for α1-AGP as a mediator of the

pharmacological effects of Tha; additionally, Tha analogs do not compete for that binding site

(Turk et al., 1996; Niwayama et al., 1998). α1-AGP is one of the major acute phase proteins in

humans, rats, mice and other species; its concentration is elevated in response to systemic

tissue injury, inflammation or infection, and these changes in serum protein concentrations

have been correlated with increases in hepatic synthesis. The α1-AGP expression is regulated

by cytokines such as TNF-α, IL-6 and IL-1β; although the exact physiological role of α1-AGP

remains still to be completed, this protein is considered as a natural antiinflammatory and

immunomodulatory endogen agent (Fournier et al., 2000; Hochepied et al., 2003).

Since Tha possesses valuable therapeutic properties but also teratogenic activity and

other side effects, various groups of research in medicinal chemistry and pharmacology

around world have synthesized and assessed diverse families of Tha analogs in order to

augment the chemical stability, the potency as TNF-α inhibitors and their immunomodulatory

efficacy, besides lowering the adverse effects (Corral et al., 1996; Marriott et al., 1998;

Muller et al., 1998; Muller et al., 1999; Hashimoto, 2008; Zahran et al., 2008; Man et al.,

2009). Some Tha analogs have been synthesized resembling its hydrolysis products (Muller et

al., 1996) and others are similar to its hydroxylated metabolites that have been demonstrated

to be potent immunomodulators (Yamamoto et al., 2009). Among the many families of novel

and promising Tha analogs, there are two of them that are outstanding as potent TNF-α

inhibitors; the first group is composed by molecules structurally and functionally very similar

to Tha, known as immunomodulatory drugs because of their marked costimulatory properties

on T cells promoting the secretion of IL-2 and IFN-γ, but these compounds also inhibit the

production of IL-1β, IL-6 and IL-12 as well as greatly increase the synthesis of IL-10, the

main antiinflammatory Th2-type cytokine in stimulated PBMC (Corral et al., 1999; Schafer et

al., 2003). The most important members of this immunomodulatory group are pomalidomide

(CC-4047, Actimid™) and lenalidomide (CC-5013, Revlimid™) (Teo, 2005); both drugs

belong to a novel generation of amino-substituted Tha analogs in the phthalimide ring (Muller

et al., 1999) (Figure 2).

On the other hand, the second group of effective TNF-α inhibitors was synthesized

resembling the structure of Tha hydrolysis products (Corral et al., 1996; Muller et al., 1996),

they also increase IL-10 (Marriott et al., 1998; Corral et al., 1999) and possess biological

activity as potent phosphodiesterase-4 (PDE-4) inhibitors while Tha is not, therefore, it

cannot be excluded that one or more of the Tha metabolites or degradation products may

inhibit that enzyme (Muller et al., 1998). PDE-4 is the primary enzyme that catalyzes the


Figure 2 Some structures of thalidomide analogs.

hydrolysis of adenosine 3´,5´-cyclic monophosphate (cAMP), as a result, the inhibitors of

PDE-4 are cAMP-elevating agents (Bender and Beavo, 2006). It is well documented that

augmented levels of cAMP inhibit the TNF- production (Cheng et al., 1997; Kast, 2000).

Thus, inhibition on PDE-4 has been shown to be an effective via for inhibition of TNF-

production in activated monocytes and PBMC by this group of compounds, especially for

perfluorinated Tha analogs (Muller et al., 1998; Niwayama et al., 1998). In addition, stable

analogs of cAMP, adenylyl cyclase activators or PDE inhibitors are capable of reducing the

activation of NF-κB and in consequence lowering TNF-α as well as other proinflammatory

cytokines (Gantner et al., 1997). Some compounds that belong to this group are: PDA, 3-


phthalimido-3-(3,4-dimethoxyphenyl)-propanoic acid; PDP, 3-phthalimido-3-(3,4-

dimethoxyphenyl)-propanamide; PDPMe, methyl 3-phthalimido-3-(3,4-dimethoxyphenyl)-

propanoate; 4NO2PDPMe, methyl 3-(4-nitrophthalimido)-3-(3,4-dimethoxyphenyl)-

propanoate; 4APDPMe, methyl 3-(4-aminophthalimido)-3-(3,4-dimethoxyphenyl)-

propanoate; TFPDPMe, methyl 3-tetrafluorophthalimido-3-(3,4-dimethoxyphenyl)-

propanoate; PEMN, 3-phthalimido-3-(3-ethoxy, 4-methoxyphenyl)-propanitrile (Muller et al.,

1996; Muller et al., 1998). Currently, apremilast (CC-10004) is perhaps the most promising

drug of this family (Man et al., 2009) (Figure 2).

Concerning the mechanisms of action of Tha and its biological effects, there are reports

about the pharmacological differences between the two Tha enantiomers, while (+)-(R)-Tha

exhibited significant positive influences on all sedative effects, the (-)-(S)-Tha had a

significant effect in the opposite direction, because it has shown the dose-dependent

teratogenic activity (Blaschke et al., 1979), besides a superior effect in preventing

splenomegaly in chicken embryos (Field et al., 1966) and in immunomodulation (Muller et

al., 1999). Other studies have reported that this drug possesses bidirectional

immunomodulatory properties, inhibiting or enhancing the TNF-α production depending on

the enantiomer administered, R or S (Miyachi et al., 1996), as well as these differential effects

have been observed in diverse cellular cultures or by using diverse cytokine inducers or

immune stimulatory agents; thus, Tha enhances 12-O-tetradecanoylphorbol-13-acetate

(TPA)-induced TNF-α production by human leukemia HL-60 cells, while it inhibits TPA-

induced TNF-α production by another leukemia cell line called THP-1, although Tha inhibits

TNF-α production by both cell types when they are stimulated with okadaic acid (OA)

(Miyachi et al., 1997a; Miyachi et al., 1997b). Furthermore, some research groups are looking

for TNF-α bidirectional modulators based on Tha derivatives, for example the compound

FPP-33 (Figure 2) (Hashimoto, 2008; Fernández-Braña et al., 2009). Therefore, experimental

differences in effectiveness between thalidomide and its analogs might be observed due to

variations in potency, stability, metabolism, pharmacokinetics, bioavailability,

enantiodependence, cellular type or to a bidirectional cytokine regulation; besides the dose,

via of administration, time courses, animal species and schedule of treatment could be other

striking factors capable of leading to a variation in the desired pharmacological

immunomodulation. Although further studies are required to clarify and optimize

immunomodulatory effects, the hopeful outcomes of these compounds on cytokines, at

systemic and hepatic level, suggest a wide perspective to use them as immunomodulatory

agents in liver diseases; this will be analyzed later on. Tables 1 and 2 summarize some

immunomodulatory effects on very important cytokines as well as some possible mechanisms

of action of Tha and its most remarkable analogs.

Thalidomide and its Analogs: Pharmacokinetics and Metabolism

The therapeutic dose of Tha as a racemic mixture is normally 100-400 mg/day for

multiple myeloma patients and higher doses of 600-1600 mg/day in graft-versus-host disease

treatments (Eriksson et al., 1995; Mujagić et al., 2002; Kamikawa et al., 2006). The absolute

bioavalability of Tha after oral intake is limited as the drug is slowly absorbed from the

gastrointestinal tract, the total absortion of Tha increases proportionally with the increase in


Table 1. Immunomodulatory properties on cytokines of some thalidomide analogs

Analogs

TNF-

IC50

(μM)

IL-1β

IC50

(μM)

IL-6

IC50

(μM)

IFN-γ

in T

cells

IL-10

Times more

potent than

Tha

inhibiting

TNF-α

Thalidomide

(Tha) 194 ↓ Yes ↓ Yes ↑ Yes ↑ Yes

1.00

4NO2PDPMe 64 NA NA NA NA 3.03

PDA 60 ↓ Yes NA NA ↑ Yes 3.23

PDP 12-13 ↓ Yes NA ↓ Yes ↑ Yes 14.92

PDPMe 2.90 ↓ Yes ↓ Yes NA Yes 66.89

CC-3052 1.22 ↓ --- ↓ --- NA ↑ Yes 159.01

4APDPMe 0.45 ↓ Yes ↓ Yes NA ↑ Yes 431.11

TFPDPMe 0.26 0.40 0.30 NA NA 746.15

PEMN 0.12 ↓ Yes ↓ Yes NA ↑ Yes 1616.66

Lenalidomide 0.10 ↓ Yes ↓ Yes ↑ Yes ↑ Yes 1940.00

Apremilast 0.077 NA NA NA NA 2519.48

Pomalidomide 0.013 ↓ Yes ↓ Yes ↑ Yes ↑ Yes 14923.07

--- No effect or slightly; ↑, Increases its production; ↓, Inhibits its production; NA, not available; IC50,

inhibitory concentration-50 (micromolar, µM) on TNF-α production as well as their effects on

other cytokines produced by LPS-stimulated peripheral blood mononuclear cells (PBMC), except

for IFN-γ in T cells. Tha ↓ IFN-γ in PBMC.

Table 2. Possible molecular mechanisms of action of thalidomide and some analogs

Analogs PDE-4

IC50 (μM)

Binding to

1-AGP

TNF- mRNA

Degradation

Thalidomide >500 Yes ↑ Yes

4NO2PDPMe NA NA NA

PDA NA NA No

PDP 9.40 NA No

PDPMe 2.50 NA No

CC-3052 3.00 NA No

4APDPMe NA NA NA

TFPDPMe 4.70 No No

PEMN 0.13 NA NA

Apremilast 0.074 NA NA

Lenalidomide >100 NA NA

Pomalidomide >100 NA NA

IC50, inhibitory concentration-50 (micromolar, µM) on phosphodiesterase-4 (PDE-4) enzyme activity;

↑, increases its degradation; NA, not available; α1-acid glycoprotein (1-AGP).


dosage from 200 to 1200 mg given once or twice daily. However, peak plasma concentrations

increase in a less than proportional manner and the time to peak plasma concentration is

delayed, indicating that Tha poor aqueous solubility affects the rate of dissolution and

absorption after oral intake. In healthy men, peak plasma levels (maximal concentration,

Cmax) of 0.8-1.4 µg/mL were obtained in a mean of 4.4 h following a single 200 mg oral dose

(Mujagić et al., 2002; Richardson et al., 2002a). In mice, fed with a diet containing 0.03 %

w/w of Tha, this drug reached a mean plasma concentration of 0.8 µg/mL (Shannon et al.,

1981) which is an equivalent concentration of 0.9 µg/mL quantified in the blood of a man

following a single oral dose of 100 mg of Tha (Faigle et al., 1962; Shannon et al., 1997);

furthermore, concentrations as high as 5.0 µg/mL of Tha in the blood have been reported

when patients were given 200 mg four times a day (Vogelsang, et al., 1992). A study in eight

healthy male volunteers, whom received once an oral dose of 200 mg of Tha, reported a

volume of distribution of 120.7 L, plasma Cmax of 1.15 µg/mL, time to maximal plasma

concentration (tmax) at 4.39 h, a mean absortion half-life of 1.7 h and a mean elimination half-

life at 8.7 h in a monocompartament model with renal excretion of 0.6 % of initial dose; that

elimination half-life is about three times longer than that observed in animals, besides that the

total body clearance rate is relatively slow 10.41 L/h (Chen et al., 1989). Other authors have

reported pharmacokinetic parameters for Tha in multiple myeloma (MM) patients in order to

offer more accuracy in data in that disease, for example, after a single dose of 200 mg of Tha

the Cmax was 1.39 µg/mL, tmax at 4.8 h, area under curve (AUC) 81.0 µmol·h/L and the

elimination half-life at 7.6 h; all those parameters were also compared with data from mice

and rabbits administered with Tha (Chung et al., 2004). Differences among races should be

taken into account when Tha is administered for the treatment of any illnesses because the

pharmacokinetic parameters may be affected as well as lower or higher effective doses would

be required (Kamikawa et al., 2006).

In spite of the efforts to separate the R and S Tha enantiomers in order to get also both

pharmacological activities apart without interference on each other, it has been observed that

Tha enantiomers racemize in vitro (Knoche and Blaschke, 1994) as well as after the

administration of one pure enantiomer it is racemized in vivo; the pharmacokinetic

parameters have been reported, the mean rate of chiral inversion of (+)-(R)-Tha and (-)-(S)-

Tha in blood at 37 °C were 0.30 and 0.31/h, respectively. In addition, rate constants of

degradation were 0.17 and 0.18/h as well as mean rates constants for in vivo inversion were

0.17/h (R to S) and 0.12/h (S to R), predominating (+)-(R)-Tha at equilibrium; also, mean

elimination rate constants were 0.079/h (R) and 0.24/h (S). Furthermore, a considerable faster

rate of elimination of the (-)-(S)-Tha was seen and the mean apparent terminal half-life of the

Tha enantiomers was 4.7 h (Eriksson et al., 1995). The interconversion of enantiomers under

quasi-physiological conditions has been observed inclusive with Tha analogs, as the case

of pomalidomide. The S-isomer of pomalidomide, which is more effective as

immunomodulatory agent than the R-isomer, undergoes a rapid racemization in 2 h,

suggesting that there is no advantage in developing the single isomer (Teo et al., 2003).

Pharmacokinetic data for lenalidomide is still in development although in healthy volunteers

the oral absorption is rapid, reaching the Cmax between 0.625 and 1.5 h post-dose. Food

reduces the Cmax by 36 %, its pharmacokinetics is linear and the AUC of 0.8 to 1.2 µmol·h/L

increases proportionately with dose. In patients suffering from MM the Cmax occurs between

0.5 and 4 h and renal half-life of elimination is around 3.1 to 4.2 h (Richardson et al., 2002b).


Regarding the family of Tha analogs inhibitors of PDE-4, the only related data to

pharmacokinetics are the half-lives reported in human plasma at 37 °C that reflects the drug

stability (Corral et al., 1996), for example, as the case of PDP its half-life is around 8 h, for

PDPMe approximately 3 h and an analog which resembles to the 4APDPMe that has a half-

life of about 4 h. The most stable Tha analog is CC-3052, which exhibits increased stability in

human plasma with a half-life of around 17.5 h versus 1.5 h for Tha (Marriott et al., 1998).

Apremilast pharmacokinetic parameters were reported in female rats orally administered with

10 mg/kg, such as Cmax of 1100 ng/mL, AUC of 1400 ng·h/mL, half-life of 5 h with 64 %

absorbed (Man et al., 2009). Differences in half-lives may reflect the solubility and stability

of each compound in organism and therefore their bioavailability; then, this is a very

important factor because some analogs could be metabolized or eliminated from organism at

different rates without reaching a significant immunomodulatory effect, a dose adjustment

may be required accordingly.

When Tha is administered orally to animals, only a small amount of the unchanged drug

is excreted in the urine and the major portion of the compound is broken down and excreted

as at least 20 transformation products (Schumacher et al., 1965b); in dogs, the little

unchanged Tha is excreted in feces preferentially. The biotransformation of Tha can occur by

non-enzymatic hydrolysis, just by spontaneous rupture catalyzed by alkaline pH, as it has

been mentioned above. Also, Tha is metabolically labile because of its biotransformation by

hepatic P450 enzyme-mediated hydroxylation, specifically CYP2C (Ando et al., 2002); two

major metabolites of Tha are 5-hydroxyTha and 5´-hydroxyTha to form then a multitude of

metabolites that have been isolated (Lepper et al., 2006). The hydrolysis products have been

detected in diverse species as well as the proportion of hydroxylated metabolites is higher in

mice than in rats and rabbits while these are almost undetectable in healthy volunteers and

MM patients (Chung et al., 2004). Hence, the possibility should be considered that the

teratogenic side effect or/and other multiple pharmacological activities might be due to the

interspecies differences in its pharmacokinetics and metabolites, including their enantiomers,

rather than Tha itself (Chung et al., 2004; Yamamoto et al., 2009). Lenalidomide is

eliminated unchanged through kidneys (two thirds of dose) in healthy volunteers and it has

been thought it that undergoes a higher hepatic metabolism than Tha.

Current Uses for Thalidomide and Some Analogs

Thanks to the discovery by Sheskin (1965) that Tha possessed striking effects on the

patients suffering from the cutaneous manifestations of ENL, in July 16, 1998, thalidomide

reemerged, since the Food and Drug Administration of United States approved its use for the

treatment of such disease (Annas and Elias, 1999). A short time later after 1965, Tha was

successfully tried in the graft-versus-host reaction in rats and man (Field et al., 1966;

Vogelsang et al., 1992); inclusive, there are current reports on this Tha application

(Ratanatharathorn et al., 2001). Based on its immunomodulatory properties that evoke an

antiinflammatory effect, Tha has been tested in clinical studies for treating MM wherein it has

shown high efficacy (Venon et al., 2009); in addition, its analog lenalidomide gained the FDA

approval in June 2006 for treating relapsed and refractory MM (Chen et al., 2009; Magarotto

and Palumbo, 2009). Tha inhibitory effects on angiogenesis (D‟Amato, et al., 1994) opened

its potential use for the treatment of many diverse diseases depending on that process, such as


cancer solid tumors (Richardson et al., 2002a) as well as for the use of Tha analogs in the

management of those ailments (Marriott et al., 1999; Teo, 2005). Rheumatoid arthritis is a

chronic and inflammatory autoimmune-related disease; Tha and its analogs have also been

tried in this illness with hopeful results (Gutierrez-Rodriguez et al., 1989; Oliver et al., 1999).

Tha and lenalidomide showed to be a successful tool in the treatment of Behçet‟s disease

(Direskeneli et al., 2008; Green et al., 2008). Furthermore, thalidomide has beneficial

properties to controlling the aphthous ulcers and cachexia associated with HIV/AIDS

(Jacobson et al., 1997; Marriott et al., 1999). Crohn‟s disease is an autoimmune inflammatory

bowel disease in which Tha has been reported to be an effective treatment for patients with

refractory episodes; additionally, there are current trials to evaluate Tha analogs in such

illness (Mansfield et al., 2007; Gordon et al., 2009).

As Tha and its analogs are clinically or experimentally being tried in many chronic,

degenerative and inflammatory diseases, there is a potential risk of producing teratogenic

outcomes in possible pregnant patients being administered with these drugs, hence, it has

been created the system for thalidomide education and prescribing safety (STEPS) that is a

strict as well as comprehensive program to control and monitor access to Tha or its analogs

(Zeldis et al., 1999). Although Tha and some analogs display teratogenic effects it is

important to keep in mind that their main therapeutic applications are for the treatment of

severe, chronic and degenerative diseases wherein patients must not get pregnant (Annas and

Elias, 1999).

Cytokines and Liver Damage

Immunomodulation on Cytokines: Restoring the Proinflammatory and

Antiinflammatory Disequilibrium

Cytokines are proteins or peptides, some of them glycosylated, produced by cells, mainly

immune cells, in response to a variety of inducing stimuli, with growth differentiation and

activation functions that regulate the nature of the immune responses or that influence the

behavior of other different cell types. Cytokines are involved in nearly every facet of

immunity and inflammation, from induction of the innate immune response to the generation

of cytotoxic T cells and the development of antibodies by the humoral immune system, as

well as they coordinate the functions of the immune system with the rest of body. The

combination of cytokines that are produced in response to an immune insult determines which

arm of the immune system will be activated. Consequently, cytokines are most distinguished

for their activities associated with inflammation, immune reactivity, tissue injury or repair and

organ dysfunction. At present, at least 70 candidate cytokines are known or genetically

predicted, they are grouped as interferons (IFNs), interleukins (ILs), colony-stimulating

factors (CSFs), transforming growth factors (TGFs) and tumor necrosis factors (TNFs)

(Clemens, 1991; Simpson et al., 1997; Rose-John, 2002; Kidd, 2003; Steinke and Borish,

2006). The distinctive pattern of effect of each cytokine depends on concentration-dependent

binding to specific receptors on the surface of the target cells and subsequent activation of

cellular machinery at the cell membrane level, or in some cases, at the level of the nucleus


and genetic machinery (Kidd, 2003); in this regard, two excellent reviews are recommended

(Grötzinger, 2002; Ishihara and Hirano, 2002).

One theory of immune regulation involves homeostasis between T-helper 1 (Th1) and T-

helper 2 (Th2) cell types activity. The Th1/Th2 hypothesis arose from 1986 research

suggesting mouse T-helper cells expressed differing cytokine patterns and other functions.

This hypothesis was adapted to human immunity, with Th1 and Th2 cells directing different

immune response pathways. Th1 cells drive the type-1 pathway of cellular immunity to fight

viruses and other intracellular pathogens or eliminate cancerous cells. Th2 cells drive the

type-2 pathway of humoral immunity, allergic responses and up-regulate antibody production

to fight extracellular organisms such as elimination of parasites; overactivation of either

pattern can cause disease, and either pathway can down-regulate the other. However, such

hypothesis cannot explain several immune actions because of human cytokine activities rarely

fall into exclusive pro-Th1 or -Th2 patterns. Th1 cells produce several characteristic

cytokines, most notably IFN-γ, IL-2 and IL-12 whereas Th2 cells produce a set of cytokines,

most notably IL-4 and IL-5. IL-10, formerly assumed to be the major means by which Th2

cells down-regulate Th1 cells, is also produced in comparable amounts by other cell types

(Farrar et al., 2002; Kidd, 2003).

As commented above, cytokines are categorized into Th1 and Th2-type cytokines, and it

seems that Th1 cytokines behave as proinflammatory mediators involved in the pathogenesis

of several diseases, included liver injury; for example, IL-12 and IFN-γ are known to be

representative proinflammatory Th1 cytokines and play a crucial role in the host defense

against bacterial infection in liver (Seki et al., 2000; Masubuchi et al., 2009), as well as the

most important proinflammatory cytokines TNF-α, IL-6 which also possesses

antiinflammatory activities, and IL-1β (Rizzardini et al., 1998; Cartmell et al., 2000).

Additionally, numerous cytokines have predominantly antiinflammatory effects, including IL-

1Ra, transforming growth factor-β (TGF-β) although this is a profibrogenic cytokine in liver

as it will be discussed later, IL-22, and the most important antiinflammatory cytokine IL-10

(Louis et al., 2003; Steinke and Borish, 2006).

When an etiological agent is present in the organism this causes a disruption on the

normal antiinflammatory/proinflammatory cytokines equilibrium, often up-regulating

excessively the proinflammatory cytokines and as a consequence down-regulating the

antiinflammatory ones; if this event is strong enough in an acute manner or chronically

persistent, this may set the basis for a disease. Thus, the immunomodulation is intended to

reestablish the balance of cytokines into the normal homeostatic levels, without depleting any

of them or exacerbating others. Th1/Th2 regulation is exceedingly complex, but its

importance is unquestionable, particularly in the study of diverse diseases and autoimmune

disorders. This is an active area of research for the design of immunomodulatory therapies

proposed either to dampen overreactive responses or to strengthen weak ones. Magic bullets

and master switches may be rare commodities in this area; nevertheless, defining all the

mechanisms controlling these processes and the use of immunomodulatory compounds such

as Tha and its derivatives will help make rational therapies to manipulate Th1/Th2 balance

during diseases (Farrar et al., 2002).


Cytokines Role in Deleterious Processes of Liver Damage

Cytokines have been implicated in the pathogenesis and progression of chronic liver

disease (CLD). Indeed, the cellular source and biological target of cytokines are not restricted

to cells of the immune system, as in the liver endothelial cells, stellate cells (Ito cells, fat-

storing cells or activated myofibroblasts), hepatic resident macrophages called Kupffer cells

(may be the most important source in liver) and hepatocytes are capable of producing and

responding to a number of different cytokines. Additionally, the liver is an important organ in

the metabolism of cytokines. All cells normally resident in the liver have the capacity to

produce cytokines, which by stimulating surrounding cells (paracrine effect) or themselves

(autocrine effect) leads to a further cytokine production and an amplification of an

inflammatory response. While some cytokines are released by resting cells in liver, the

concentrations and variety of cytokines released are considerably increased following

stimulation by a variety of inducers, such as bacterial endotoxin or lipopolysaccharides (LPS),

viruses, chemical agents, cancer, liver ischaemia-reperfusion and alcohol consumption

(Simpson et al., 1997). Hepatic uptake of circulating cytokines is inhibited by alcohol and this

may contribute to the elevated levels of TNF-α and IL-6 observed in such patients, in fact,

cytotoxic cytokines likely induce liver cell death by both necrosis and apoptosis in alcoholic

liver disease. Anticytokine therapy has been highly successful in attenuating cell injury/death

in a variety of toxin-induced models of liver injury, including alcohol-related liver injury

(McClain et al., 1999).

There are many hepatic disorders or diseases wherein the effect of cytokines has been

proved as a key part of those deleterious processes, as well as during liver injury and

inflammation; furthermore, cytokines also are implicated in the normal hepatic function and

metabolism as well as in liver regeneration (Simpson et al., 1997; Galun and Axelrod, 2002;

Gao, 2005). Particularly, the proinflammatory and pronecrotic TNF-α functions as two edged

sword in the liver, this cytokine is required for normal hepatocyte proliferation during liver

regeneration. It functions both as a comitogen and to induce the transcription factor NF-κB

which has antiapoptotic effects. On the other hand, TNF-α is the mediator of cholestasis and

hepatotoxicity in many animal models, including those involving the toxins concanavalin-A

and LPS. TNF-α has also been implicated as an important pathogenic mediator in patients

with alcoholic liver disease and viral hepatitis (Green et al., 1996; Bradham et al., 1998).

In experimental animal models, such as the bile duct ligation (BDL) in rats that induces a

stable and frank secondary biliary cirrhosis by chronic cholestasis, the plasma and liver levels

of proinflammatory/antiinflammatory cytokines and NO are modified when compared to

normal rats; those changes are related to biochemical markers of cholestasis, necrosis and

fibrosis (Fernández-Martínez et al., 2006). Whereas in clinical studies, the serum levels of IL-

1β, IL-6, TNF-α, IFN-γ, and C-reactive protein (CRP) have been found elevated in patients

with CLD. Cirrhotic patients with CLD show higher serum levels in IL-1β, IL-6, TNF-α, and

CRP than noncirrhotic cases. Elevated concentrations of cytokines represent a characteristic

feature of CLD regardless of underlying disease (Tilg et al., 1992). Regarding the cytokine

gene expression in cirrhotic and noncirrhotic human liver, data suggest that TGF-β has a

predominant role in liver fibrosis. Whereas, IL-1β, 6, 8, TNF-α, and IFN-γ, appear to

participate in the pathogenesis of the mild to severe inflammatory phenomena seen in

alcoholic and post-hepatitis C liver cirrhosis, respectively. Also, data indicate that neither


IFN-γ nor IL-10, at least at the levels observed in post-hepatitis C liver cirrhosis, are able to

counteract the fibrotic/inflammatory processes (Llorente et al., 1996).

Summarizing there is increasing evidence that several cytokines mediate the deleterious

hepatic inflammation, apoptosis, and necrosis of liver cells, as well as the characteristic

chronic processes cholestasis and fibrosis, previous to the end stage cirrhosis (Tilg, 2001).

Throughout CDL the relationship among chronic hepatocellular damage, liver inflammation

and cirrhosis has not been clearly defined, but cytokines could be the common link between

these complex pathological outcomes (Llorente et al., 1996).

Thalidomide Effects on Liver Damage

and Cirrhosis

Thalidomide Effects on Liver Damage

Alcoholic liver disease is maybe one of the most important hepatopathies around the

world. In this regard, the effect of Tha has been studied in an animal model of alcohol-

induced liver damage; the sensitization of Kupffer cells to LPS and the overproduction of

TNF-α are critical for progression of alcoholic liver injury. The treatment with ethanol for 8

weeks caused marked steatosis, necrosis, and inflammation in the liver. These pathologic

parameters were diminished markedly by treatment with Tha. In a 4-week ethanol group, the

LPS-induced liver damage was aggravated and Kupffer cells were sensitized to LPS.

Coadministration of thalidomide with ethanol prevented the sensitization of those cells

completely. Furthermore, thalidomide abolished the LPS-induced increase in CD14 (this is a

functional LPS receptor on macrophages/monocytes and neutrophils) expression and

intracellular calcium concentration [Ca2+

]i elevation in the macrophages. Moreover,

thalidomide reduced the LPS-induced TNF-α production by Kupffer cells by decreasing TNF-

α mRNA. Thus, Tha prevented alcoholic liver injury through suppression of TNF-α

production and abolishment of Kupffer cells sensitization (Enomoto et al., 2002; Enomoto et

al., 2004)

Activation of Kupffer cells by LPS plays a pivotal role in the onset of pathophysiological

events that occur during endotoxemia and septic shock, as well as [Ca2+

]i is involved in LPS-

stimulated cytokine production, as the case of TNF-α which is mostly produced by Kupffer

cells. TNF-α plays a key role in the initiation and progression of multiple organ failure

syndrome induced by septic shock as well as in the cholestasis provoked by sepsis (Van

Amersfoort et al., 2003; Moseley, 2004). Enomoto and coworkers (2003) determined whether

Tha could prevent LPS-induced liver injury, they found that LPS caused focal necrosis with

neutrophil infiltration in the liver. Moreover, LPS dramatically increased ALT/AST. These

pathologic parameters and increases of serum transaminases were diminished markedly by

Tha. In isolated Kupffer cells, LPS-induced increases in [Ca2+]i and TNF-α production were

suppressed by treatment with Tha. To further explore the mechanism by which Tha directly

abrogated Kupffer cell sensitivity to LPS, they determined the effect of Tha in vitro on LPS-

induced [Ca2+]i response and TNF-α production. With the addition of Tha to the culture

media before LPS, these parameters were suppressed. They concluded that Tha prevents LPS-

induced liver injury via mechanisms dependent on the suppression of TNF-α production from


Kupffer cells. The immunomodulatory effects of Tha have been evidenced in other two

models of sepsis, the first of Escherichia coli sepsis in vivo in rat as well as in in vitro by

using human monocytes (Giamarellos-Bourboulis et al., 2003), and the second in sepsis by

multidrug-resistant Pseudomonas aeruginosa (Giamarellos-Bourboulis et al., 2005); in those

studies Tha inhibited the microbial-induced NO, TNFα and IL-1β but not IL-6, as well as

increased the survival rate in septic rats.

Concerning the evaluation of Tha analogs in animal models of liver injury as

hepatoprotective drugs, there are three current reports. Thiele and coworkers (2002)

synthesized and assessed the immunomodulatory and hepatoprotective properties of a Tha

analog named TFBA, which was found to be an TNF-α, IL-6 and IL-10 inhibitor in isolated

and stimulated monocytes; this drug is not either a PDE-4 inhibitor or costimulator of T cells.

When TFBA was administered to mice with hepatic injury by galactosamine/LPS, it

diminished the ALT activity, TNF-α production but not IL-6; however this drug increased the

hepatoprotective IL-10. Furthermore, a serial of Tha analogs have been synthesized and

evaluated as immunomodulatory agents in liver and plasma in an acute model of LPS-induced

septic challenge in rat. Animal groups were twice administered with Tha or its analogs in an

equimolar dose. Two hours after last dose, rats were injected with saline or LPS. The

cytokines TNF-α, IL-6, -1β and -10 were quantified and studied in plasma and liver. After

two hours of LPS-induction, different patterns of measured cytokines were observed with Tha

analogs administration evidencing their immunomodulatory effects in both tissues.

Interestingly, some analogs decreased significantly plasma and hepatic levels of LPS-induced

proinflammatory TNF-α and others increased plasma concentration of antiinflammatory IL-

10. Tha analogs also showed slight effects on the remaining proinflammatory cytokines in

both tissues. Differences among immunomodulatory effects of analogs might be related to

potency, mechanism of action, and half lives (Fernández-Martínez et al., 2004). Finally,

hepatic glycogen metabolism is altered by NO during endotoxic shock and the previously

tested serial of Tha analogs immunomodulate the endotoxin-induced cytokines which regulate

the NO release. Therefore, the short-term effects of those Tha analogs were assessed on the

hepatic glycogen store and on the plasma and hepatic NO in an acute model of endotoxic

challenge in rat. Endotoxin caused inverse dose-dependent effects increasing plasma NO and

lowering hepatic glycogen. Tha analogs showed short-term regulatory effects on glycogen,

some of them increased it. Plasma NO was almost unaffected by analogs but hepatic NO was

strikingly modulated. Analogs slightly up-regulated the liver IFN-γ (a known NO-coinducer)

and two of them increased it significantly. Due to their interesting effects the Tha analogs

may be used as a pharmacological tool due to their short-term regulatory effects on glycogen

and NO during endotoxic shock, since drugs that increase glycogen may improve liver injury

in early sepsis (Fernández-Martínez et al., 2008).

Thalidomide Effects on Fibrosis, Cirrhosis and its Complications

Cholestasis is defined as a disorder of cholepoiesis and bile secretion as well as

mechanical or functional stoppage of the bile flow in intrahepatic or extrahepatic bile ducts,

with bile components passing into the blood. Persistent cholestasis with concomitant

inflammatory and connective tissue reactions as well as all forms of chronic cholangitis may

lead to irreversible cholestasis and, after long-term, to biliary fibrosis (excessive


accumulation of collagen) with preserved liver structure or to the last phase known as biliary

cirrhosis (Kuntz and Kuntz, 2006). Secondary biliary cirrhosis induced in rat by BDL is a

widespread experimental model (Kountouras et al., 1984). Tha and two analogs, PDP and

PDA, have been assessed as hepatoprotective agents during BDL (Fernández-Martínez et al.,

2001; Fernández-Martínez et al., 2009). Tha showed a poor improvement on biochemical

markers of liver damage when compared to those afforded by PDP. That analog protected

from liver injury since it diminished alkaline phosphatase (AP, cholestasis marker) and

alanine aminotransferase (ALT, indicator of necrosis) activities, as well as bilirubins

(indicator of cholestasis) and prevented collagen accumulation significantly; while

thalidomide showed only modest beneficial effects on bilirubins and ALT. PDP diminished

the increase in plasma TNF-α levels induced by BDL, while thalidomide not only failed to

inhibit this cytokine, but slightly increased it. PDA is a water soluble analog that also

improved cholestasis, necrosis and fibrosis outcomes in the BDL model. Histopathology

showed remarkable liver damage amelioration due to Tha and even better for both analogs.

The effectiveness of these Tha analogs has been related to its potency as TNF-α and PDE-4

inhibitors, therefore, inhibiting proinflammatory cytokines results in decreased necrosis,

cholestasis and fibrosis in biliary secondary cirrhosis (Tilg, 2001).

Carbon tetrachloride (CCl4)-induced liver damage is a very used animal model, wherein

cytokines are involved too (Recknagel et al., 1989; DeCicco et al., 1998); chronic

administration of this hepatotoxicant produces cirrhosis similar to that induced by alcoholism.

In that model Tha has showed promising effects in several papers. Muriel and coworkers

(2003) reported by first time the effect of Tha during the chronic intoxication with CCl4 that

induced 33.3% mortality, while Tha cotreatment reduced it to 13.3%. The serum activities of

ALT, γ-glutamyl transpeptidase (GGTP, marker of cholestasis) and AP increased 3, 2 and 4-

fold by CCl4 treatment; Tha completely prevented elevation of these enzymes. Hepatic lipid

peroxidation increased about 20-fold and glycogen was abolished in CCl4-cirrhotic rats; Tha

completely diminished the former and partially the later. Histology showed that CCl4-treated

rats receiving Tha had minor histological alterations and thinner bands of collagen. The

antifibrotic effect estimated by collagen was partial but significant. Thus, Tha ameliorated the

cirrhosis induced by CCl4. Similar results were obtained by other authors using this model, in

addition, they have found that Tha might exert an effect on the inhibition of oxidative stress

via down-regulation of NF-κB signaling pathway to prevent the progression of liver cirrhosis;

it may be due to the oxidative stress parameters such as superoxide dismutase, glutathione

peroxidase and malondialdehyde as well as the expression of NF-κBp65, TGF-β (the most

potent profibrogenic cytokine) and the tissue inhibitor of metalloproteinase-1 (TIMP-1, this

protein inhibits the collagenase activity) were significantly diminished in CCl4-cirrhotic rats

treated with Tha (Lv et al., 2006a). In addition, some authors have proposed that Tha is able

to prevent or to reverse, in an established CCl4-induced cirrhosis model, the liver damage and

fibrosis by down-regulation of NF-κB activation because of the inhibition on the degradation

of the inhibitor of NF-κB (IκB) as well as NF-κB-induced adhesion molecules like

intracellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1)

and E-selectin, these adhesion molecules are very important in the process of recruitment and

migration of inflammatory cells provoked by endothelial activation in cirrhosis; furthermore,

as a consequence, levels of hyaluronic acid, laminin, procollagen-III and collagen-IV are

diminished by the antifibrotic effects of Tha (Lv et al., 2006b; Paul et al., 2006; Lv et al.,

2007; Xiao et al., 2007).


Tha has shown to be a very good hepatoprotective as well as antifibrotic agent in two

more models of cirrhosis. Yeh and coworkers (2004) demonstrated the hepatoprotective and

antifibrotic effects of Tha in the model of thioacetamide-induced cirrhosis, given that this

drug improved the survival rate, reduced the expression of TNF-α, TGF-β, TIMP-1 and

TIMP-2 in rats; moreover, they verified in vitro that the Kupffer cells isolated from Tha-

treated rats had suppressed the production of TNF-α and TGF-β. Furthermore, similar

antifibrotic effects reported for Tha have been studied in the model of dimethylnitrosamine-

induced cirrhosis. In such experiment Tha also diminished in vivo the fibrosis scores of

cirrhotic livers from intoxicated rats, the content of collagen as well as the NF-κB positive

cells were reduced, and that the mRNA expressions of TGF-β, collagen 1α2, TNF-α and

iNOS genes were attenuated by Tha. The same authors tried Tha on rat hepatic stellate cells

(HSC-T6) in vitro, they found that Tha inhibited in a concentration-dependent manner the

NF-κB transcriptional activity induced by TNF-α, incluiding IκB kinase-α (IKKα) and IκB

phosphorylation, as well as lowered the TGF-β-induced collagen deposition in these stellate

cells (Chong et al., 2006). For further reference regarding the NF-κB activation and its

regulation in liver as well as the relationship TGF-β/liver fibrosis four excellent reviews are

recommended (Fallowfield et al., 2006; Gieling et al., 2008; Iimuro and Brenner, 2008; Sun

and Karin, 2008).

In addition to the hopeful results obtained by Tha as discussed for experimental models

of fibrosis and cirrhosis, it rises interesting to comment briefly about the experimental and

clinical effects of Tha on the portal hypertension, that is a clinical syndrome very common in

cirrhotic patients, whom later may develop gastroesophageal variceal bleeding (Sanyal et al.,

2008). The first report concerning this issue was in an animal model of portal hypertension,

wherein rats were administered with Tha; this drug inhibited the TNF-α synthesis, reduced

the NO production, blunted the development of hyperdynamic circulation and decreased the

portal pressure (López-Talavera et al., 1996). Other two experimental approaches have been

recently done by using cirrhotic BDL-rats; fist, the chronic administration of Tha improved

the portal-systemic collateral vascular responsiveness to arginine-vasopressin in cholestatic

rats, which was partially related to the inhibition of the cytokine vascular endothelial growth

factor (VEGF) (Chang et al., 2009), and second, Tha decreased portal venous pressure as well

as the intrahepatic resistance by reducing the hepatic thromboxane-A2, a potent

vasoconstrictor (Yang et al., 2009). An open pilot study in patients with stable alcoholic-

cirrhosis and esophageal varices were administered with Tha or with pentoxifylline

(immunomodulatory drug and PDE inhibitor); Tha, but not pentoxiphylline, reduced the

hepatic venous pressure as well as TNF-α levels, that suggested future controlled clinical

trials (Austin et al., 2004). Finally, a patient study case of intractable bleeding from

hypertensive gastropathy secondary to extrahepatic portal vein obstruction was managed

successfully by Tha (Karajeh et al., 2006).

Thalidomide in Experimental and Clinical Hepatocellular Carcinoma (HCC)

One of the first approaches to use Tha in liver diseases was perhaps its application in

primary biliary cirrhosis (PBC), an idiopathic autoimmune disease with many clinical and

pathological similarities to other illnesses wherein Tha had been successful; thus, a double-

blind placebo controlled pilot study was performed, nonetheless, there were no improvements


in liver function tests or in liver histology. A number of patients treated with Tha reported an

improvement in pruritus. That study suggested that Tha was unlikely to be affective in PBC

(McCormick et al., 1994). Later, after the renaissance of Tha for the treatment of MM, the

next obvious step was using this drug in several clinical trials for the treatment of HCC,

which is the fifth most common cancer in the world and the third cause of cancer-related

mortality. Cirrhosis is the main risk factor underlying HCC, and there is a clear association

between chronic infections with hepatitis B and C virus, excessive alcohol consumption,

cirrhosis and HCC; however, HCC also occurs in a noncirrhotic liver and the need of a

systemic therapy is urgent (Witjes et al., 2009). Experimentally, Tha alone has significantly

evidenced to inhibit angiogenesis and metastasis of HCC in the nude mice model, besides its

inhibitory effects on TNF-α (Zhang et al., 2005a). Also, Tha in combination with paclitaxel

(Zhang et al., 2005b) or with doxorubicin (Yang et al., 2005) afforded synergistic and

significant necrosis and growth inhibitory effects on tumors, reduced angiogenesis and

metastasis. These experimental results encouraged the Tha assessment in clinical trials.

Tha effects in clinical evaluations for treating HCC have yielded varied outcomes. Some

authors have documented very promising effects, since individual case studies (Quek et al.,

2006) or several patients in phase II clinical studies have responded to Tha therapy alone or in

combination with other drugs (Wang et al., 2004; Demeria et al., 2007) and with radiotherapy

(Hsu et al., 2006). Although Tha as a single treatment might not have very good results,

because of the modest effects obtained in most cases (3-6 %), for example reducing the

tumors size and/or achieving the stabilization of the disease for a longer period (Lin et al.,

2005; Chuah et al., 2007); consequently, authors strongly recommend the use of Tha in

combination with other chemotherapeutic agents, including the new immunomodulatory Tha

analogs, to treat early small but not large tumors (Walder, 2005; Pinter et al., 2008).

Generally Tha side effects are reported as well tolerated for patients, although few

publications claim that this drug is not well tolerated when it is administered with other

adjuvant agents (Cappa et al., 2005; Schwartz et al., 2005). As a unique case, it has been

reported the successful treatment with oral Tha of a male patient (52 years old) who was

suffering from hepatic epithelioid hamangioendothelioma (HEH) and lung metastasis, that

cancer type is a very rare vascular tumor of the liver with an unpredictable malignant

potential; Tha inhibited the growth and progression of the tumor (Mascarenhas et al., 2004).

Adverse Effects by Thalidomide: Hepatotoxicity

As commented above, Tha is a relatively safe drug compared with other known

teratogens due to its very low acute toxicity, LD50 of >5000 mg/kg in mice and rabbits

(Somers, 1960; Williams, 1968). The low toxicity of Tha has been observed in man, as 20

cases of accidental or intentional overdosage had been reported and all recovered eventfully

(Somers, 1960), it may be possible that the absence of toxicity is due to the limited

absorption. Regardless that, the common side effects during treatment with Tha are sedation,

constipation, fatigue, skin rash and peripheral neuropathy (Singhal et al., 1999); less

frequently bradycardia, hypotension and hypothyroidism have been described during

prolonged treatments, but often well tolerated by patients, as it has been commented for Tha

administration in MM and HCC clinical trials.


However, recent case reports concerning extremely rare but existing Tha hepatotoxicity

in patients have been published. Post marketing surveillance of Tha since reintroduction in

1998 has identified one case where the cause of death was thought to be directly due to

treatment with Tha (Clark et al., 2001). One case of Tha-induced fulminant hepatic failure

which proved to be fatal in a 64-year-old woman has also been described (Hamadani et al.,

2007). Almost the rest of cases have also been elder patients (57-79 years old) and just one

younger woman (36) undergoing refractory MM with some complications as hypertension,

diabetes, renal failure or leukemia and one with stable chronic hepatitis C; none of them had

previously manifested hepatic alterations as well as their liver function tests in plasma were

normal before beginning Tha treatment (Trojan et al., 2003; Dabak and Kuriakose, 2009;

Levesque and Bradette, 2009). In addition, there are documented cases of hepatotoxicity but

due to lenalidomide treatment in MM patients (Hussein, 2005; Hussain, 2007). Two patients

with advanced HCC whom were under Tha therapy developed tumor lysis syndrome (TLS),

similar to other two patients that received Tha for the treatment of MM (Spencer et al., 2003;

Lee et al., 2006). Most cases returned to normal or quasinormal plasma values of liver

damage biochemical markers (ALT, AST, AP and bilirubins), after Tha dosage cessation.

Therefore, it becomes increasingly important to identify patient groups that may be

particularly susceptible to specific adverse drug effects and to identify conditions under which

specific adverse events may be more likely to occur. Oncology patients may represent a

patient population with increased susceptibility to Tha-associated adverse effects (Clark et al.,

2001).

It is necessary to comment that in no one of the diverse experiments in animal models of

liver damage herein reviewed, and performed by several authors, Tha or its analogs

administered in acute or chronic manner have showed by themselves either any sign of

hepatotoxicity or a negative modification on the liver injury indicators during their

evaluation, as well as they have not affected the normal plasma and liver cytokine profiles in

control groups; what is more, even when some models are really drastic or severe (CCl4,

BDL, LPS, dimethylnitrosamine and thioacetamide) Tha or its analogs have resulted

hepatoprotective agents, that has also been assessed by histopathology. There is only one

report about exacerbation of acetaminophen hepatotoxicity by Tha, nevertheless authors did

not find any significant influence on normal plasma levels of liver damage markers by the

only administration of Tha (Kröger et al.; 1995).

Conclusion

In spite of the current medical advances and the development of new expensive therapies

for the treatment of liver diseases and their last stage cirrhosis, nowadays there are not enough

nor successfully effective and secure systemic drugs to guarantee a much better quality of life

or the cure to the patients suffering from those illnesses (Muriel and Rivera-Espinoza, 2008).

Nevertheless, immunomodulation seems to be a complex but very promising pharmacological

approach to reestablish the cytokine imbalance during the liver damage and cirrhosis, this in

order to manipulate or possibly to control the deleterious and beneficial processes that those

mediators of inflammation regulate and, as a consequence, to maintain their levels into the

normal liver and systemic homeostasis. Therefore, on the basis of all the reports herein


reviewed, including pro and con analyzed, the use of Tha and its analogs is suggested as

potential hepatoprotective immunomodulatory drugs, although it is very clear that further and

deeper basic as well as clinical research is necessary to detail the ratio risk/benefit.

References

Ando, Y; Fuse, E; Figg, WD. Thalidomide metabolism by the CYP2C subfamily. Clin

Cancer Res. 2002;8:1964-73.

Annas, GJ; Elias, S. Thalidomide and the Titanic: reconstructing the technology tragedies of

the twentieth century. Am J Public Health, 1999;89:98-101.

Austin, AS; Mahida, YR; Clarke, D; Ryder, SD; Freeman, JG. A pilot study to investigate the

use of oxpentifylline (pentoxifylline) and thalidomide in portal hypertension secondary to

alcoholic cirrhosis. Aliment Pharmacol Ther. 2004;19:79-88.

Bender, AT; Beavo, JA. Cyclic nucleotide phosphodiesterases: molecular regulation to

clinical use. Pharmacol Rev. 2006;58:488-520.

Blaschke, G; Kraft, HP; Fickentscher, K; Köhler F. Chromatographic separation of racemic

thalidomide and teratogenic activity of its enantiomers. Arzneimittelforschung.

1979;29:1640-2.

Bradham, CA; Plümpe, J; Manns, MP; Brenner, DA; Trautwein, C. Mechanisms of hepatic

toxicity I. TNF-induced liver injury. Am J Physiol. 1998;275(3 Pt 1):G387-92.

Cappa, FM; Cantarini, MC; Magini, G; Zambruni, A; Bendini, C; Santi, V; Bernardi, M;

Trevisani, F. Effects of the combined treatment with thalidomide, megestrol and

interleukine-2 in cirrhotic patients with advanced hepatocellular carcinoma. A pilot study.

Dig Liver Dis. 2005;37:254-9.

Carcache de-Blanco, E; Pandit, B; Hu, Z; Shi, J; Lewis, A; Li, PK. Inhibitors of NF-κB

derived from thalidomide. Bioorg Med Chem Lett. 2007;17:6031-5.

Cartmell, T; Poole, S; Turnbull, AV; Rothwell, NJ; Luheshi, GN. Circulating interleukin-6

mediates the febrile response to localised inflammation in rats. J Physiol. 2000;526 Pt

3:653-61.

Chang, CC; Wang, SS; Huang, HC; Lee, FY; Lin, HC; Lee, JY; Chen, YC; Lee, SD. Chronic

thalidomide administration enhances vascular responsiveness to vasopressin in portal-

systemic collaterals of bile duct-ligated rats. J Chin Med Assoc. 2009;72:234-42.

Chen, C; Reece, DE; Siegel, D; Niesvizky, R; Boccia, RV; Stadtmauer, EA; Abonour, R;

Richardson, P; Matous, J; Kumar, S; Bahlis, NJ; Alsina, M; Vescio, R; Coutre, SE;

Pietronigro, D; Knight, RD; Zeldis, JB; Rajkumar, V. Expanded safety experience with

lenalidomide plus dexamethasone in relapsed or refractory multiple myeloma. Br J

Haematol. 2009;146:164-70.

Chen, TL; Vogelsang, GB; Petty, BG; Brundrett, RB; Noe, DA; Santos, GW; Colvin, OM.

Plasma pharmacokinetics and urinary excretion of thalidomide after oral dosing in

healthy male volunteers. Drug Metab Dispos Biol Fate Chem. 1989;17:402-5.

Cheng, JB; Watson, JW; Pazoles, CJ; Eskra, JD; Griffiths, RJ; Cohan, VL; Turner, CR;

Showell, HJ; Pettipher, ER. The phosphodiesterase type 4 (PDE4) inhibitor CP-80,633

elevates plasma cyclic AMP levels and decreases tumor necrosis factor-alpha (TNFalpha)

production in mice: effect of adrenalectomy. J Pharmacol Exp Ther. 1997;280:621-6.


Chong, LW; Hsu, YC; Chiu, YT; Yang, KC; Huang, YT. Anti-fibrotic effects of thalidomide

on hepatic stellate cells and dimethylnitrosamine-intoxicated rats. J Biomed Sci.

2006;13:403-18.

Chuah, B; Lim, R; Boyer, M; Ong, AB; Wong, SW; Kong, HL; Millward, M; Clarke, S; Goh,

BC. Multi-centre phase II trial of thalidomide in the treatment of unresectable

hepatocellular carcinoma. Acta Oncol. 2007;46:234-8.

Chung, F; Lu, J; Palmer, BD; Kestell, P; Browett, P; Baguley, BC; Tingle, M; Ching, LM.

Thalidomide pharmacokinetics and metabolite formation in mice, rabbits, and multiple

myeloma patients. Clin Cancer Res. 2004;10:5949-56.

Clark, TE; Edom, N; Larson, J; Lindsey, LJ. Thalomid (Thalidomide) capsules: a review of

the first 18 months of spontaneous postmarketing adverse event surveillance, including

off-label prescribing. Drug Saf. 2001;24:87-117.

Clemens, MJ. Cytokines: Introduction to cytokines. In: Read AP, Brown T editors. Medical

perspectives series. Oxford, UK: Ed. Bioscientific publishers; 1991; 1-20.

Corral, LG; Haslett, PAJ; Muller, GW; Chen, R; Wong, LM; Ocampo, CJ; Patterson, RT;

Stirling, DI; Kaplan, G. Differential cytokine modulation and T cell activation by two

distinct classes of thalidomide analogues that are potent inhibitors of TNF-. J Immunol.

1999;163:380-6.

Corral, LG; Muller, GW; Moreira, AL; Chen, Yuxi; Wu, M; Stirling, D; Kaplan, G. Selection

of novel analogs of thalidomide with enhanced tumor necrosis factor-α inhibitory

activity. Mol Med. 1996;2:506-15.

Dabak, V; Kuriakose, P. Thalidomide-induced severe hepatotoxicity. Cancer Chemother

Pharmacol. 2009;63:583-5.

D‟Amato, RJ; Loughnan, MS; Flynn, E; Folkman, J. Thalidomide is an inhibitor of

angiogenesis. Proc Natl Acad Sci USA, 1994;91:4082-5.

DeCicco, LA; Rikans, LE; Tutor, CG; Hornbrook, KR. Serum and liver concentrations of

tumor necrosis factor α and interleukin-1β following administration of carbon

tetrachloride to male rats. Toxicol Lett 1998;98:115-21.

Demeria, D; Birchall, I; Bain, VG. Dramatic reduction in tumour size in hepatocellular

carcinoma patients on thalidomide therapy. Can J Gastroenterol. 2007;21:517-8.

Direskeneli, H; Ergun, T; Yavuz, S; Hamuryudan, V; Eksioglu-Demiralp, E. Thalidomide has

both anti-inflammatory and regulatory effects in Behcet‟s disease. Clin Rheumatol.

2008;27:373-5.

Enomoto, N; Takei, Y; Hirose, M; Ikejima, K; Kitamura, T; Sato, N. Thalidomide prevents

alcoholic liver injury in rats through inhibition of Kupffer cell sensitization. Comp

Hepatol. 2004;3 Suppl 1:S37.

Enomoto, N; Takei, Y; Hirose, M; Ikejima, K; Miwa, H; Kitamura, T; Sato, N. Thalidomide

prevents alcoholic liver injury in rats through suppression of Kupffer cell sensitization

and TNF-alpha production. Gastroenterology, 2002;123:291-300.

Enomoto, N; Takei, Y; Hirose, M; Kitamura, T; Ikejima, K; Sato, N. Protective effect of

thalidomide on endotoxin-induced liver injury. Alcohol Clin Exp Res. 2003;27 Suppl:2S-

6S.

Eriksson, T; Björkman, S; Roth, B; Fyge, Å; Höglund, P. Stereospecific determination, chiral

inversion in vitro and pharmacokinetics in humans of the enantiomers of thalidomide.

Chirality, 1995;7:44-52.


Fabro, S; Schumacher, H; Smith, RL; Stagg, RBL; Williams, RT. The metabolism of

thalidomide: some biological effects of thalidomide and its metabolites. Brit J

Pharmacol. 1965; 25:352-62.

Faigle, JW; Kerberle, HR; Schmid, K. The metabolic fate of thalidomide. Experientia,

1962;18:389.

Fallowfield, JA; Kendall, TJ; Iredale, JP. Reversal of fibrosis: no longer a pipe dream? Clin

Liver Dis. 2006;10:481-497.

Farrar, JD; Asnagli, H; Murphy, KM. T helper subset development: roles of instruction,

selection, and transcription. J Clin Invest. 2002;109:431-5.

Fernández-Braña, M; Acero, N; Añorbe, L; Muñoz-Mingarro, D; Llinares, F; Domínguez, G.

Discovering a new analogue of thalidomide which may be used as a potent modulator of

TNF-alpha production. Eur J Med Chem. 2009;44:3533-42.

Fernández-Martínez, E; Morales-Ríos, MS; Pérez-Álvarez, V; Muriel, P. Effects of

thalidomide and 3-phthalimido-3-(3,4-dimethoxyphenyl)-propanamide on bile duct

obstruction-induced cirrhosis in the rat. Drug Dev Res. 2001;54:209-18.

Fernández-Martínez, E; Morales-Ríos, MS; Pérez-Álvarez, V; Muriel, P. Immunomodulatory

effects of thalidomide analogs on LPS-induced plasma and hepatic cytokines in the rat.

Biochem Pharmacol. 2004;68:1321-9.

Fernández-Martínez, E; Pérez-Álvarez, V; Tsutsumi, V; Shibayama, M; Muriel, P. Chronic

bile duct obstruction induces changes in plasma and hepatic levels of cytokines and nitric

oxide in the rat. Exp Toxicol Pathol. 2006;58:49-58.

Fernández-Martínez, E; Pérez-Hernández, N; Muriel, P; Pérez-Álvarez, V; Shibayama, M;

Tsutsumi, V. The thalidomide analog 3-phthalimido-3-(3,4-dimethoxyphenyl)-propanoic

acid improves the biliary cirrhosis in the rat. Exp Toxicol Pathol. 2009;61:471-9.

Fernández-Martínez, E; Wens-Flores, I; Moreno-G, M; Ortiz, MI; Muriel, P; Pérez-Álvarez,

V. Short-term effects of thalidomide analogs on hepatic glycogen and nitric oxide in

endotoxin-challenged rats. Gen Physiol Biophys. 2008;27:203-10.

Field, EO; Gibbs, JE; Tucker, DF; Hellmann, K. Effect of thalidomide on the graft versus

host reaction. Nature, 1966;211:1308-10.

Fournier, T; Medjoubi-N, N; Porquet, D. Alpha-1-acid glycoprotein. Biochim Biophys Acta,

2000;1482:157-71.

Fujimoto, H; Noguchi, T; Kobayashi, H; Miyachi, H; Hashimoto, Y. Effects of

immunomodulatory derivatives of thalidomide (IMiDs) and their analogs on cell-

differentiation, cyclooxygenase activity and angiogenesis. Chem Pharm Bull.

2006;54:855-60.

Fujita, J; Mestre, JR; Zeldis, JB; Subbaramaiah, K; Dannenberg, AJ. Thalidomide and its

analogues inhibit lipopolysaccharide-mediated Iinduction of cyclooxygenase-2. Clin

Cancer Res. 2001;7:3349-55.

Fullerton, PM; Kremer, M. Neuropathy after intake of thalidomide (Distaval). Brit Med J.

1961;2:855-8.

Galun, E; Axelrod, JH. The role of cytokines in liver failure and regeneration: potential new

molecular therapies. Biochim Biophys Acta, 2002;1592:345-358.

Gantner, F; Küsters, S; Wendel, A; Hatzelmann, A; Schudt, C; Tiegs, G. Protection from T

cell-mediated murine liver failure by phosphodiesterase inhibitors. J Pharmacol Exp

Ther. 1997;280:53-60.

Gao, B. Cytokines, STATs and liver disease. Cell Mol Immunol. 2005;2:92-100.


Giamarellos-Bourboulis, EJ; Bolanos, N; Laoutaris, G; Papadakis, V; Koussoulas, V; Perrea,

D; Karayannacos, PE; Giamarellou, H. Immunomodulatory intervention in sepsis by

multidrug-resistant Pseudomonas aeruginosa with thalidomide: an experimental study.

BMC Infect Dis. 2005;5:51.

Giamarellos-Bourboulis, EJ; Poulaki, H; Kostomitsopoulos, N; Dontas, I; Perrea, D;

Karayannacos, PE; Giamarellou, H. Effective immunomodulatory treatment of

Escherichia coli experimental sepsis with thalidomide. Antimicrob Agents Chemother,

2003;47:2445-9.

Gieling, RG; Burt, AD; Mann, DA. Fibrosis and cirrhosis reversibility - molecular

mechanisms. Clin Liver Dis. 2008;12:915-937.

Gordon, JN; Prothero, JD; Thornton, CA; Pickard, KM; Di Sabatino, A; Goggin, PM; Pender,

SL; MacDonald, TT. CC-10004 but not thalidomide or lenalidomide inhibits lamina

propria mononuclear cell TNF-α and MMP-3 production in patients with inflammatory

bowel disease. J Crohn’s Colitis, 2009;3:175-82.

Green, J; Upjohn, E; McCormack, C; Zeldis, J; Prince, HM. Successful treatment of Behçet‟s

disease with lenalidomide. Br J Dermatol. 2008;158:197-8.

Green, RM; Beier, M; Gollan, JL. Regulation of hepatic bile salt transporters by endotoxin

and inflammatory cytokines in rodents. Gastroenterology, 1996;111:193-8.

Grötzinger, J. Molecular mechanisms of cytokine receptor activation. Biochim Biophys Acta,

2002;1592:215-23.

Gutiérrez-Rodríguez, O; Starusta-Bacal, P; Gutiérrez-Montes, O. Treatment of refractory

rheumatoid arthritis the thalidomide experience. J Rheumatol. 1989;16:158-63.

Hamadani, M; Benson, DM Jr; Copelan, EA. Thalidomide-induced fulminant hepatic failure.

Mayo Clin Proc. 2007;82:638.

Hashimoto, Y. Thalidomide as a multi-template for development of biologically active

compounds. Arch Pharm. (Weinheim) 2008;341:536-47.

Hochepied, T; Berger, FG; Baumann, H; Libert, C. Alpha(1)-acid glycoprotein: an acute

phase protein with inflammatory and immunomodulating properties. Cytokine Growth

Factor Rev. 2003;14:25-34.

Hsu, WC; Chan, SC; Ting, LL; Chung, NN; Wang, PM; Ying, KS; Shin, JS; Chao, CJ; Lin,

GD. Results of three-dimensional conformal radiotherapy and thalidomide for advanced

hepatocellular carcinoma. Jpn J Clin Oncol. 2006;36:93-9.

Hussain, S; Browne, R; Chen, J; Parekh, S. Lenalidomide-induced severe hepatotoxicity.

Blood, 2007;110:3814.

Hussein, MA. Lenalidomide: patient management strategies. Semin Hematol. 2005;42:S22-5.

Iimuro, Y; Brenner, DA. Matrix metalloproteinase gene delivery for liver fibrosis. Pharm

Res. 2008;25:249-58.

Ishihara, K; Hirano, T. Molecular basis of the cell specificity of cytokine action. Biochim

Biophys Acta, 2002;1592:281-96.

Jacobson, JM; Greenspan, JS; Spritzler, J; Ketter, N; Fahey, JL; Jackson, JB; Fox, L;

Chernoff, M; Wu, AW; MacPhail, LA; Vasquez, GJ; Wohl, DA. Thalidomide for the

treatment of oral aphthous ulcers in patients with human immunodeficiency virus

infection. National Institute of Allergy and Infectious Diseases AIDS Clinical Trials

Group. N Engl J Med. 1997;336:1487-93.


Kamikawa, R; Ikawa, K; Morikawa, N; Asaoku, H; Iwato, K; Sasaki, A. The

pharmacokinetics of low-dose thalidomide in Japanese patients with refractory multiple

myeloma. Biol Pharm Bull. 2006;29:2331-4.

Karajeh, MA; Hurlstone, DP; Stephenson, TJ; Ray-Chaudhuri, D; Gleeson, DC. Refractory

bleeding from portal hypertensive gastropathy: a further novel role for thalidomide

therapy? Eur J Gastroenterol Hepatol, 2006, 18, 545-8.

Kast, RE. Tumor necrosis factor has positive and negative self regulatory feed back cycles

centered around cAMP. Int J Immunopharmacol 2000;22:1001-6.

Keller, H; Kunz, W; Muckter, H. N-phthalyl-glutamic acid imide: experimental studies on a

new synthetic product with sedative properties. Arzneimittelforschung, 1956;6:426-30.

Kidd, P. Th1/Th2 balance: the hypothesis, its limitations, and implications for health and

disease. Altern Med Rev. 2003;8:223-46.

Kim, YS; Kim, JS; Jung, HC; Song, IS. The effects of thalidomide on the stimulation of NF-

kappaB activity and TNF-alpha production by lipopolysaccharide in a human colonic

epithelial cell line. Mol Cells, 2004;17:210-6.

Knoche, B; Blaschke, G. Investigations on the in vitro racemization of thalidomide by high-

performance liquid chromatography. J Cromatography, 1994, 666, 235-40.

Kountouras, J; Billing, BH; Scheuer, PJ. Prolonged bile duct obstruction: a new experimental

model for cirrhosis in the rat. Br J Exp Pathol. 1984;65:305-11.

Kröger, H; Klewer, M; Grätz, R; Dietrich, A; Ockenfels, H; Miesel, R. Exacerbation of

acetaminophen hepatotoxicity by thalidomide and protection by nicotinic acid amide.

Gen Pharmacol. 1995;26:1243-7.

Kuntz, E; Kuntz, HD. Hepatology: principles and practice. Germany: Springer Medizin

Verlag Heidelberg; 2006.

Lee, CC; Wu, YH; Chung, SH; Chen, WJ. Acute tumor lysis syndrome after thalidomide

therapy in advanced hepatocellular carcinoma. Oncologist, 2006;11:87-8.

Lenz, W. Kindliche misbildungen nach medikament-einnehmen während de gravidität. Dtsch

Med Wochenschr. 1961; 86:2555-6.

Lenz, W. A personal perspective on the thalidomide tragedy. Teratology, 1992;46:417-8.

Lepper, ER; Smith, NF; Cox, MC; Scripture, CD; Figg, WD. Thalidomide metabolism and

hydrolysis: mechanisms and implications. Curr Drug Metab. 2006;7:677-85.

Levesque, E; Bradette, M. Hepatotoxicity as a rare but serious side effect of thalidomide. Ann

Hematol. 2009;88:183-4.

Lin, AY; Brophy, N; Fisher, GA; So, S; Biggs, C; Yock, TI; Levitt, L. Phase II study of

thalidomide in patients with unresectable hepatocellular carcinoma. Cancer,

2005;103:119-25.

Llorente, L; Richaud-Patin, Y; Alcocer-Castillejos, N; Ruiz-Soto, R; Mercado, MA; Orozco,

H; Gamboa-Domínguez, A; Alcocer-Varela, J. Cytokine gene expression in cirrhotic and

non-cirrhotic human liver. J Hepatol. 1996;24:555-63.

López-Talavera, JC; Cadelina, G; Olcowski, J; Merrill, W; Groszmann, RJ. Thalidomide

inhibits tumor necrosis factor , decreases nitric oxide synthesis, and ameliorates the

hyperdynamic circulatory syndrome in portal hypertensive rats. Hepatology,

1996;23:1616-21.

Louis, H; Le Moine, O; Goldman, M; Devière, J. Modulation of liver injury by interleukin-

10. Acta Gastroenterol Belg. 2003;66:7-14.


Lv, P; Luo, HS; Zhou, XP; Paul, SC; Xiao, YJ; Si, XM; Liu, SQ. Thalidomide prevents rat

liver cirrhosis via inhibition of oxidative stress. Pathol Res Pract. 2006a;202:777-88.

Lv, P; Paul, SC; Xiao, Y; Liu, S; Luo, H. Effects of thalidomide on the expression of

adhesion molecules in rat liver cirrhosis. Mediators Inflamm 2006b; DOI:

10.1155/MI/2006/93253.

Lv, P; Luo, HS; Zhou, XP; Xiao, YJ; Paul, SC; Si, XM; Zhou, YH. Reversal effect of

thalidomide on established hepatic cirrhosis in rats via inhibition of nuclear factor-

B/inhibitor of nuclear factor-B pathway. Arch Med Res. 2007;38:15-27.

Magarotto, V; Palumbo, A. Evolving role of novel agents for maintenance therapy in

myeloma. Cancer J. 2009;15:494-501.

Majumdar, S; Lamothe, B; Aggarwal, BB. Thalidomide suppresses NF-kappa B activation

induced by TNF and H2O2, but not that activated by ceramide, lipopolysaccharides, or

phorbol ester. J Immunol. 2002;168:2644-51.

Man, HW; Schafer, P; Wong, LM; Patterson, RT; Corral, LG; Raymon, H; Blease, K;

Leisten, J; Shirley, MA; Tang, Y; Babusis, DM; Chen, R; Stirling, D; Muller, GW.

Discovery of (S)-N-[2-[1-(3-ethoxy-4-methoxyphenyl)-2-methanesulfonylethyl]-1,3-

dioxo-2,3-dihydro-1H-isoindol-4-yl] acetamide (apremilast), a potent and orally active

phosphodiesterase 4 and tumor necrosis factor-alpha inhibitor. J Med Chem.

2009;52:1522-4.

Mansfield, JC; Parkes, M; Hawthorne, AB; Forbes, A; Probert, CS; Perowne, RC; Cooper, A;

Zeldis, JB; Manning, DC; Hawkey, CJ. A randomized, double-blind, placebo-controlled

trial of lenalidomide in the treatment of moderately severe active Crohn‟s disease.

Aliment Pharmacol Ther. 2007;26:421-30.

Marriott, JB; Muller, G; Dalgleish, AG. Thalidomide as an emerging immunotherapeutic

agent. Immunol Today, 1999;20:538-40.

Marriott, JB; Westby, M; Cookson, S; Guckian, M; Goodbourn, S; Muller, G; Shire, MG;

Stirling, D; Dalgleish, AG. CC-3052: A water-soluble analog of thalidomide and potent

inhibitor of activation-induced TNF- production. J Immunol. 1998;161:4236-43.

Mascarenhas, RC; Sanghvi, AN; Friedlander, L; Geyer, SJ; Beasley, HS; Van Thiel, DH.

Thalidomide inhibits the growth and progression of hepatic epithelioid

hemangioendothelioma. Oncology, 2004;67:471-5.

Masubuchi, Y; Sugiyama, S; Horie, T. Th1/Th2 cytokine balance as a determinant of

acetaminophen-induced liver injury. Chem Biol Interact. 2009;179:273-9.

McBride, WB. Thalidomide and congenital abnormalities. Lancet, 1961;2:1358.

McClain, CJ; Barve, S; Deaciuc, I; Kugelmas, M; Hill, D. Cytokines in alcoholic liver

disease. Semin Liver Dis. 1999;19:205-19.

McCormick, PA; Scott, F; Epstein, O; Burroughs, AK; Scheuer, PJ; McIntyre, N.

Thalidomide as therapy for primary biliary cirrhosis: a double-blind placebo controlled

pilot study. J Hepatol. 1994;21:496-9.

McHugh, SM; Rifkin, IR; Deighton, J; Wilson, AB; Lachmann, PJ; Lockwood, CM; Ewan,

PW. The immunosuppressive drug thalidomide induces T helper cell type 2 (Th2) and

concomitantly inhibits Th1 cytokine production in mitogen- and antigen-stimulated

human peripheral blood mononuclear cell cultures. Clin Exp Immunol. 1995;99:160-7.


Miyachi, H; Azuma, A; Hioki, E; Iwasaki, S; Hashimoto, Y. Enantio-dependence of inducer-

specific bidirectional regulation of tumor necrosis factor (TNF)-alpha production: potent

TNF-α production inhibiting. Bioorg Med Chem Lett 1996;6:2293-8.

Miyachi, H; Azuma, A; Ogasawara, A; Uchimura, E; Watanabe, N; Kobayashi, Y; Kato, F;

Kato, M; Hashimoto, Y. Novel biological response modifiers: phthalimides with tumor

necrosis factor-α production-regulating activity. J Med Chem 1997a;40:2858-65.

Miyachi, H; Ogasawara, A; Azuma, A; Hashimoto, Y. Tumor necrosis factor-alpha

production-inhibiting activity of phthalimide analogues on human leukemia THP-1 cells

and a structure-activity relationship study. Bioorg Med Chem 1997b;5:2095-102.

Moreira, AL; Corral, LG; Ye, W; Johnson, B; Stirling, D; Muller, GW; Freedman, VH;

Kaplan, G. Thalidomide and thalidomide analogs reduce HIV type 1 replication in human

macrophages in vitro. AIDS Res Hum Retroviruses 1997;13:857-63.

Moreira, AL; Sampaio, EP; Zmuidzinas, A; Frindt, P; Smith, KA; Kaplan, G. Thalidomide

exerts its inhibitory action tumor necosis factor- by enhancing mRNA degration. J Exp

Med, 1993, 177, 1675-80.

Moseley, RH. Sepsis and cholestasis. Clin Liver Dis 2004;8:83-94.

Mujagić, H; Chabner, BA; Mujagić, Z. Mechanisms of action and potential therapeutic uses

of thalidomide. Croat Med J 2002;43:274-85.

Muller, GW; Chen, R; Hauang, SY; Corral, LG; Wong, LM; Patterson, RT; Shire, MG; Chen,

Y; Kaplan, G; Stirling, DI. Amino-substituted thalidomide analogs: potent inhibitors of

TNF- production. Bioorg Med Chem Lett 1999;9:1625-30.

Muller, GW; Corral, LG; Shire, MG; Wang, H; Moreira, A; Kaplan, G; Stirling, DI.

Structural modifications of thalidomide produce analogs with enhanced tumor necrosis

factor inhibitory activity. J Med Chem 1996; 39: 3238-40.

Muller, GW; Shire, MG; Wong, LM; Corral, LG; Patterson, RT; Chen, Y; Stirling, DI.

Thalidomide analogs and PDE4 inhibition. Bioorg Med Chem Lett 1998;8:2669-74.

Muriel, P; Fernández-Martínez, E; Pérez-Álvarez, V; Lara-Ochoa, F; Ponce, S; García, J;

Shibayama, M; Tsutsumi, V. Thalidomide ameliorates carbon tetrachloride induced

cirrhosis in the rat. Eur J Gastroenterol Hepatol 2003;15:951-7.

Muriel, P; Rivera-Espinoza, Y. Beneficial drugs for liver diseases. J Appl Toxicol

2008;28:93-103.

Niwayama, S; Loh, C; Turk, BE; Liu, JO; Miyachi, H; Hashimoto, Y. Enhanced potency of

perfluorinated thalidomide derivatives for inhibition of LPS-induced tumor necrosis

factor- production is associated with a change of mechanism of action. Bioorg Med

Chem Lett 1998;8:1071-6.

Oliver, SJ; Freeman, SL; Corral, LG; Ocampo, CJ; Kaplan, G. Thalidomide analogue

CC1069 inhibits development of rat adjuvant arthritis. Clin Exp Immunol 1999;118:315-

21.

Paul, SC; Lv, P; Xiao, YJ; An, P; Liu, SQ; Luo, HS. Thalidomide in rat liver cirrhosis:

blockade of tumor necrosis factor- via inhibition of an inhibitor of nuclear factor-B.

Pathobiology 2006;73:82-92.

Pinter, M; Wichlas, M; Schmid, K; Plank, C; Müller, C; Wrba, F; Peck-Radosavljevic, M.

Thalidomide in advanced hepatocellular carcinoma as antiangiogenic treatment approach:

a phase I/II trial. Eur J Gastroenterol Hepatol 2008;20:1012-9.


Quek, R; Lim, ST; Ong S. Hepatocellular carcinoma - Pathological complete response to oral

capecitabine, megestrol and thalidomide. Acta Oncol 2006;45:95-7.

Ratanatharathorn, V; Ayash, L; Lazarus, HM; Fu, J; Uberti, JP. Chronic graft-versus-host

disease: clinical manifestation and therapy. Bone Marrow Transplant 2001;28:121-9.

Recknagel, RO; Glende, EA Jr; Dolak, JA; Waller, RL. Mechanisms of carbon tetrachloride

toxicity. Pharmacol Ther 1989;43:139-54.

Richardson, P; Hideshima, T; Anderson, K. Thalidomide: emerging role in cancer medicine.

Annu Rev Med 2002a;53:629-57.

Richardson, PG; Schlossman, RL; Weller, E; Hideshima, T; Mitsiades, C; Davies, F;

LeBlanc, R; Catley, LP; Doss, D; Kelly, K; McKenney, M; Mechlowicz, J; Freeman, A;

Deocampo, R; Rich, R; Ryoo, JJ; Chauhan, D; Balinski, K; Zeldis, J; Anderson, KC.

Immunomodulatory drug CC-5013 overcomes drug resistance and is well tolerated in

patients with relapsed multiple myeloma. Blood 2002b;100:3063-7.

Rizzardini, M; Zappone, M; Villa, P; Gnocchi, P; Sironi, M; Diomede, L; Meazza, C;

Monshouwer, M; Cantoni, L. Kupffer cell depletion partially prevents hepatic heme

oxygenase 1 messenger RNA accumulation in systemic inflammation in mice: role of

interleukin 1beta. Hepatology 1998;27:703-10.

Rose-John, S. Cytokines come of age. Biochim Biophys Acta 2002;1592:213-4.

Sampaio, EP; Sarno, EN; Galilly, R; Cohn, ZA; Kaplan, G. Thalidomide selectively inhibits

tumor necrosis factor- production by stimulated human monocytes. J Exp Med, 1991,

173, 699-703.

Sanyal, AJ; Bosch, J; Blei, A; Arroyo, V. Portal hypertension and its complications.

Gastroenterology 2008;134:1715-28.

Schafer, PH; Gandhi, AK; Loveland, MA; Chen, RS; Man, HW; Schnetkamp, PP; Wolbring,

G; Govinda, S; Corral, LG; Payvandi, F; Muller, GW; Stirling, DI. Enhancement of

cytokine production and AP-1 transcriptional activity in T cells by thalidomide-related

immunomodulatory drugs. J Pharmacol Exp Ther 2003;305:1222-32.

Schumacher, H; Smith, RL; Williams, RT. The metabolism of thalidomide: the spontaneous

hydrolysis of thalidomide in solution. Brit J Pharmacol 1965a; 25:324-37.

Schumacher, H; Smith, RL; Williams, RT. The metabolism of thalidomide: the fate of

thalidomide and some of its hydrolysis products in various species. Brit J Pharmacol

1965b; 25:338-51.

Schwartz, JD; Sung, M; Schwartz, M; Lehrer, D; Mandeli, J; Liebes, L; Goldenberg, A;

Volm, M. Thalidomide in advanced hepatocellular carcinoma with optional low-dose

interferon-alpha2a upon progression. Oncologist 2005;10:718-27.

Seki, S; Habu, Y; Kawamura, T; Takeda, K; Dobashi, H; Ohkawa, T; Hiraide, H. The liver as

a crucial organ in the first line of host defense: the roles of Kupffer cells, natural killer

(NK) cells and NK1.1 Ag+ T cells in T helper 1 immune responses. Immunological

reviews 2000;174:35-46.

Shannon, EJ; Miranda, RO; Morales, MJ; Hastings, EC. Inhibition of the novo antibody

synthesis by thalidomide as a relevant mechanism of action in leprosy. Scand J Immunol

1981;13:17-25.

Shannon, EJ; Morales, MJ; Sandoval, F. Immunomodulatory assays to study structure-

activity relationships of thalidomide. Immunopharmacol 1997;35:203-12.

Sheskin, J. Thalidomide in the treatment of lepra reactions. Clin Pharmacol Ther 1965;6:303-

6.


Shimazawa, R; Sano, H; Tanatani, A; Miyachi, H; Hashimoto, Y. Thalidomide as a nitric

oxide synthase inhibitor and its structural development. Chem Pharm Bull 2004;52:498-

9.

Simpson, KJ; Lukacs, NW; Colletti, L; Strieter, RM; Kunkel, SL. Cytokines and the liver. J

Hepatol 1997;27:1120-32.

Singhal, S; Mehta, J; Desikan, R; Ayers, D; Roberson, P; Eddlemon, P; Munshi, N; Anaissie,

E; Wilson, C; Dhodapkar, M; Zeddis, J; Barlogie, B. Antitumor activity of thalidomide in

refractory multiple myeloma. N Engl J Med 1999;341:1565-71.

Somers, GF. Pharmacological properties of thalidomide (α-phthalimidoglutarimide), a new

sedative hypnotic drug. Brit J Pharmacol 1960;15:111-6.

Somers, GF. Thalidomide and congenital abnormalities. Lancet 1962;1:912-3.

Spencer, A; Robert, A; Bailey, M; Schran, H; Lynch, K. No evidence for an adverse

interaction between zoledronic acid and thalidomide: preliminary safety analysis from the

Australasian Leukemia and Lymphoma Group MM6 Myeloma Trial. Blood

2003;102:383.

Steinke, JW; Borish, L. 3. Cytokines and chemokines. J Allergy Clin Immunol

2006;117:S441-5.

Suizu, M; Muroya, Y; Kakuta, H; Kagechika, H; Tanatani, A; Nagasawa, K; Hashimoto Y.

Cyclooxygenase inhibitors derived from thalidomide. Chem Pharm Bull 2003;51:1098-

102.

Sun, B; Karin, M. NF-κB signaling, liver disease and hepatoprotective agents. Oncogene

2008;27:6228-44.

Teo, SK. Properties of thalidomide and its analogues: implications for anticancer therapy.

AAPS J 2005;7:E14-9.

Teo, SK; Chen, Y; Muller, GW; Chen, RS; Thomas, SD; Stirling, DI; Chandula, RS. Chiral

inversion of the second generation IMiD™ CC-4047 (ACTIMID™) in human plasma

and phosphate-buffered saline. Chirality 2003;15:348-51.

Thiele, A; Bang, R; Gütschow, M; Rossol, M; Loos, S; Eger, K; Tiegs, G; Hauschildt, S.

Cytokine modulation and suppression of liver injury by a novel analogue of thalidomide.

Eur J Pharmacol 2002;453:325-34.

Tilg, H. Cytokines and liver diseases. Can J Gastroenterol 2001;15:661-8.

Tilg, H; Wilmer, A; Vogel, W; Herold, M; Nölchen, B; Judmaier, G; Huber, C. Serum levels

of cytokines in chronic liver diseases. Gastroenterology 1992;103:264-74.

Trojan, A; Chasse, E; Gay, B; Pichert, G; Taverna, C. Severe hepatic toxicity due to

thalidomide in relapsed multiple myeloma. Ann Oncol 2003;14:501-2.

Turk, BE; Jiang, H; Liu, JO. Binding of thalidomide to 1-acid glycoprotein may be involved

in its inhibition of tumor necrosis factor production. Proc Natl Acad Sci USA

1996;93:7552-6.

Van Amersfoort, ES; Van Berkel, TJ; Kuiper, J. Receptors, mediators, and mechanisms

involved in bacterial sepsis and septic shock. Clin Microbiol Rev. 2003;16:379-414.

Venon, MD; Roccaro, AM; Gay, J; Moreau, AS; Dulery, R; Facon, T; Ghobrial, IM; Leleu,

X. Front line treatment of elderly multiple myeloma in the era of novel agents. Biologics.

2009;3:99-109.


Vogelsang, GB; Farmer, ER; Hess, AD; Altamonte, V; Beschorner, WE; Jabs, DA; Corio,

RL; Levin, LS; Colvin, OM; Wingard, JR; Santos, GW. Thalidomide for the treatment of

chronic graft-versus-host disease. New Eng J Med. 1992;326:1055-8.

Wadler, S. Thalidomide for advanced hepatocellular carcinoma, is this a real alternative?

Cancer, 2005;103:1-4.

Wang, TE; Kao, CR; Lin, SC; Chang, WH; Chu, CH; Lin, J; Hsieh, RK. Salvage therapy for

hepatocellular carcinoma with thalidomide. World J Gastroenterol. 2004;10:649-53.

Wang, T; Zhang, YH; Kong, XW; Lai, YS; Ji, H; Chen, YP; Peng, SX. Synthesis and

biological evaluation of nitric oxide-donating thalidomide analogues as anticancer agents.

Chem Biodivers. 2009;6:466-74.

Williams, RT. Thalidomide: a study of biochemical teratology. Arch Environ Health,

1968;16:493-502.

Witjes, CD; Verhoef, C; Verheul, HM; Eskens, FA. Systemic treatment in hepatocellular

carcinoma; 'A small step for man...'. Neth J Med. 2009;67:86-90.

Wnendt, S; Finkam, M; Winter, W; Ossig, J; Raabe, G; Zwingenberger, K. Enantioselective

inhibition of TNF-α release by thalidomide and thalidomide analogues. Chirality,

1996;8:390-6.

Xiao, YJ; Luo, HS; Lv, P. Effects of thalidomide on adhesion molecules in rat liver fibrosis.

World Chinese J Digestol. 2007;15:3372-6.

Yamamoto, T; Shibata, N; Sukeguchi, D; Takashima, M; Nakamura, S; Toru, T; Matsunaga,

N; Hara H; Tanaka, M; Obata, T; Sasaki, T. Synthesis, configurational stability and

stereochemical biological evaluations of (S)- and (R)-5-hydroxythalidomides. Bioorg

Med Chem Lett. 2009;19:3973-6.

Yang, YM; Du, GJ; Lin, HH. Experimental study of thalidomide for treatment of murine

hepatocellular carcinoma. Di Yi Jun Yi Da Xue Xue Bao (J First Mil Med Univ)

2005;25:925-8.

Yang, YY; Huang, YT; Lin, HC; Lee, FY; Lee, KC; Chau, GY; Loong, CC; Lai, CR; Lee,

SD. Thalidomide decreases intrahepatic resistance in cirrhotic rats. Biochem Biophys Res

Commun. 2009;380:666-72.

Yeh, TS; Ho, YP; Huang, SF; Yeh, JN; Jan, YY; Chen, MF. Thalidomide salvages lethal

hepatic necroinflammation and accelerates recovery from cirrhosis in rats. J Hepatol.

2004;41:606-12.

Zahran, MA; Salem, TA; Samaka, RM; Agwa, HS; Awad, AR. Design, synthesis and

antitumor evaluation of novel thalidomide dithiocarbamate and dithioate analogs against

Ehrlich ascites carcinoma-induced solid tumor in Swiss albino mice. Bioorg Med Chem.

2008;16:9708-18.

Zeldis, JB; Williams, BA; Thomas, SD; Elsayed, ME. S.T.E.P.S.: a comprehensive program

for controlling and monitoring access to thalidomide. Clin Ther, 1999, 21, 319-30.

Zhang, ZL; Liu, ZS; Sun, Q. Effects of thalidomide on angiogenesis and tumor growth and

metastasis of human hepatocellular carcinoma in nude mice. World J Gastroenterol.

2005a;11:216-20.

Zhang, ZL; Liu, ZS; Sun, Q. Anti-tumor effect of thalidomide and paclitaxel on

hepatocellular carcinoma in nude mice. Chin Med J. (Engl) 2005b;118:1688-94.

Zwingenberger, K; Wnendt, S. Immunomodulation by thalidomide: systematic review of the

literature and of unpublished observations. J Inflamm. 1995-1996;46:177-211.

thalidomide and liver cirrhosis

Health & Medicine